181–190 of 459 posts
So they forgot to "geographically disparate" fence their queries. Having built a flight navigation system before, I know this bug. I've seen this bug. I've followed the spec to include a geofence to avoid this bug.
Why on earth do they not have GUIDs for these navigation points if the names are not globally unique and inter-region routes are commonplace?
Great post. This part goes too far, I think: > Human lives were kept safe at all times > The consequence of all this was not that any human lives were put in danger, .. When you're arguing that cancelling 2000 flights cost £100M and that no human danger was incurred, something should feel off. That might be around 600k humans who weren't able to be where they felt they needed to be. Did they have somewhere safe to sl…
This is a great post. My reading of it: - waypoint names used around the world are not unique - as a sortof cludge, "In order to avoid confusion latest standards state that such identical designators should be geographically widely spaced." - but still you might get the same waypoint name used twice in a route to mean different places - the software was not written with that possibilty in mind - route did not compute…
Earlier quoted context omitted.
Because the code classified it as a "this should never happen!" error, and then it happened. The code didn't classify it as a "flight plan has bad data" error or a "flight plan data is OK but we don't support it yet" error. If a "this should never happen!" error occurs, then you don't know what's wrong with the system or how bad or far-reaching the effects are. Maybe it's like what happened here and you could have co…
I agree with the general sentiment "if you see an unexpected error, STOP", but I don't really think that applies here. That is, when processing a sequential queue which is what this job does, it seems to me reading the article that each job in the queue is essentially totally independent. In that case, the code most definitely should isolate "unexpected error in job" from a larger "something unknown happened processi…
This is a great post. My reading of it: - waypoint names used around the world are not unique - as a sortof cludge, "In order to avoid confusion latest standards state that such identical designators should be geographically widely spaced." - but still you might get the same waypoint name used twice in a route to mean different places - the software was not written with that possibilty in mind - route did not compute…
My jaw kept dropping with each new bullet point.
Earlier quoted context omitted.
Because the code classified it as a "this should never happen!" error, and then it happened. The code didn't classify it as a "flight plan has bad data" error or a "flight plan data is OK but we don't support it yet" error. If a "this should never happen!" error occurs, then you don't know what's wrong with the system or how bad or far-reaching the effects are. Maybe it's like what happened here and you could have co…
And that's why I never (or very rarely) put "this should never happen" exceptions anymore in my code Because you eventually figure out that, yes, it does happen
That would have grounded only the plane with the flight plan that the UK system could not process.
Still a bug but with less effects to all the continent, because planes that could not get inside or outside the UK could not fly and that affected all of Europe and possibly more.
So they forgot to "geographically disparate" fence their queries. Having built a flight navigation system before, I know this bug. I've seen this bug. I've followed the spec to include a geofence to avoid this bug.
Why on earth do they not have GUIDs for these navigation points if the names are not globally unique and inter-region routes are commonplace?
I.E. Yankee = YANKY. The pilot and ATC must be location aware. Apparently their software does not.
Earlier quoted context omitted.
You have to reduce that to the (still massive) set of IDs that are somewhat pronounceable in languages that use the Latin script. You don't want to be the air traffic controller trying to work out how to say 'Lufthansa 451, fly direct QXKCD'. Nonetheless, I think the there is little cause for concern about changing existing IDs. There might be sentimental attachment, but it takes barely a few flights before the new I…
I thought that is what the "ICAO pronunciation" was for? "Fly direct Quebec Xray Kilo Charlie Delta"
For example, Hungarian waypoints, at least the more important ones are normally named after cities, towns or other geographical locations near them, and use the locations name or abbreviated name, being careful that they can be pronounced reasonably easily for English speakers. Like: ERGOM (for the city Esztergom), ABONY (for the town Füzesabony), SOPRO (for Sopron), etc.
Earlier quoted context omitted.
To be fair, the article suggests early on that sometimes these plans are being processed for flights already in the air (although at least 4 hours away from the UK). If you can stop the specific problematic plane taking off then keeping the system running is fine, but once you have a flight in the air it's a different game. It's not totally unreasonable to say "we have an aircraft en route to enter UK airspace and we…
> "we have an aircraft en route to enter UK airspace and we don't know when or where - stop planning more flights until we know where that plane is". Flight plans don't tell where the plane is. Where is this assumption coming from?
Great post. This part goes too far, I think: > Human lives were kept safe at all times > The consequence of all this was not that any human lives were put in danger, .. When you're arguing that cancelling 2000 flights cost £100M and that no human danger was incurred, something should feel off. That might be around 600k humans who weren't able to be where they felt they needed to be. Did they have somewhere safe to sl…